A crash program to build missile defense would have two side benefits, each of which ultimately is far more important than the Korean matter as such.

First, it would awaken America’s long-dormant engine of scientific innovation, threatening to leapfrog the advances that Russia and China have made in defense technology. America’s competitors remember that communism collapsed during the late 1980s when the Soviet economy could not keep up with US advances in computation and avionics. Restoring US technological supremacy will make Moscow and Beijing more likely to act sensibly on other matters of contention, for example Ukraine and the Middle East.

Second, it would generate a productivity impulse that would help reverse the long secular decline in US productivity growth. Virtually all the technologies that make up the modern economy, from cheap and powerful integrated circuits to sensors, LED (light-emitting diode) screens, flat panels, optical networks and the Internet arose from the technological exigencies of the Cold War.